title: Lower calyceal occlusion by autologous blood clot to prevent stone fragment reaccumulation after retrograde intra-renal surgery for lower calyceal stones: first experience of a new technique.
abstract: OBJECTIVE
  We tested the hypothesis that lower calyceal (LC) autologous blood clot (ABC) occlusion, after retrograde intra-renal surgery (RIRS) may prevent LC fragment reaccumulation where all fragments cannot be directly removed.
  
  
  METHODS
  Over two years, patients with LC stones >6 mm <2 cm, that had presented de-novo or failed primary SWL or PNL elsewhere, were treated with RIRS. After intra-renal relocation into a favorable lie, stones were fragmented with Holmium laser energy to <3 mm, suitable for spontaneous passage. The LC was filled with 5-10 cc venous autologous blood with the patient in reverse Trendelenberg, leaving the blood to clot. After confirmatory pyelogram a DJ stent was placed. Ultrasound and KUB at 3 months assessed stone free rate.
  
  
  RESULTS
  This technique was tested in 35 patients with LC calculi (16 as primary treatment, and 19 as salvage for residual fragments post SWL or PNL). Nine salvage patients had indwelling DJ stents (three significantly encrusted at RIRS). Nine unstented patients had upper ureteral tortuosities or narrowing limiting multiple instrument passes for stone removal. Median maximum stone dimension was 1.2 cm. All were successfully relocated & fragmented. A Nitinol basket was required for stone relocation in 60%. All but one occlusion procedures succeeded at the first attempt. None required re-admission for clot colic. Only 8.6% required more than overnight hospital stay. Three and six month stone free rates were 94% and 97% respectively.
  
  
  CONCLUSIONS
  The simple LC autologous blood clot occlusion technique after RIRS, for difficult LC stones, validates our hypothesis and results in excellent stone free rates, while minimizing ureteral trauma from multiple instrument passages needed for active fragment removal. This study supports the need for multi-center experience of this technique to validate our results.
authors.affiliation: Department of Urology, St. Mary's Hospital at Imperial College School of Medicine, Praed Street, London, W2 1NY UK. anup.patel@imperial.ac.uk
authors.forename: Anup
authors.initials: A
authors.lastname: Patel
mesh_terms: D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000517:prevention & control* / Q000628:therapy*; D007670:Kidney Calices / Q000473:pathology* / Q000601:surgery*; D053844:Lasers, Solid-State; D008297:Male; D010316:Particle Size; D011187:Posture; D014567:Urography